There is growing evidence of the clinical benefits of real-time 3-D ultrasound for transthoracic cardiovascular applications using 2-D array transducers as originally developed in our laboratories at Duke University. More recently we have achieved a number of significant advances by expanding real time 3D echocardiography to intra-cardiac (3D-ICE), intra-vascular (3D-IVUS), transesophageal (3D-TEE) and thoracoscopic and laparoscopic (3D-LUS) applications by developing 2D array transducers at the tips of catheters and endoscopic probes for the guidance of minimally invasive cardiovascular procedures. The last decade has also seen tremendous breakthroughs in the development and application of interventional medical devices including vascular stents, aortic aneurysm stent grafts, vena cava filters, vascular occluders, cardiac occluders, prosthetic cardiac valves, and catheter and needle delivery of radio frequency ablation. Each minimally invasive procedure involves extensive real time imaging to guide the deployment of these devices currently requiring long periods of x-ray fluoroscopy with its inherent disadvantages of ionizing radiation exposure, poor tissue contrast and requirement for nephrotoxic contrast agents in angiography. Our hypothesis is that we can develop new generations of miniature 2D array transducers integrated into the deployment kits for these interventional devices to enable real time 3D ultrasound scanning for improved guidance of minimally invasive procedures. Thus in our specific aims we will extend our previous advances in cardiovascular real time 3D ultrasound by developing integrated catheter array transducers to guide the implantation of two important interventional cardiovascular devices from those listed above. We propose: (1) To investigate 3D ultrasound guidance of the deployment of the vena cava filter which prevents a venous thrombus from embolizing to the pulmonary circulation. (2) To investigate 3D ultrasound guidance of the aortic stent graft which isolates a weakened abdominal aortic aneurysm wall from the arterial circulation. (3) To conduct in vitro and in vivo evaluation of integrated catheter arrays for the aortic aneurysm stent graft and vena cava filter. Our long term goals are to significantly reduce exposure to ionizing radiation and x-ray contrast agents during these procedures while working toward the possibility of bedside implantation of vena cava filters and evaluating the patency of the aortic stent graft and its associated vasculature.